There is a solar version of the Fenix 6 (the slightly less ridiculously priced sportswatch brother of the MARQ series), and according to most reviews, it barely

There is a solar version of the Fenix 6 (the slightly less ridiculously priced sportswatch brother of the MARQ series), and according to most reviews, it barely makes a dent on battery life. I wouldn't hold my breath for self-sufficiency.